The difference between compact and spongy bone is that spongy bone has air packets between cells, and compact bone are a lot of cells tightly pack to one another.
compact bone contains very few spaces, it is the external part of all bones, it provides us with support. The osteon is the basic unit of the compact bone. The compact bone is full of canals and little spaces. The structure of the compact bone is a shape of a target. It has rings surrounding the central canal. Spongy bone doesn't contain osteons and no central canal. It forms most of the epiphyses of the long bone. Red bonr marrow is found in spaces between trabecube.
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